Carrying out a qualitative evidence synthesis – Examples of method-
specific data extraction and synthesis
Prof Jane NoyesAcknowledgement Ruth Garside QIMG – sharing slides
Not for wider distribution or use without permission
Examples of data extraction and synthesis I: Thematic synthesis
• Echoes thematic analysis in primary qualitative research
• Several different types of thematic synthesis
• Data extraction approach needs to be appropriate for the specific type of thematic synthesis methodology
Origins
• Echoes thematic analysis in primary qualitative research• May use line by line coding or extract themes before
coding• Codes often descriptive, but may build up to be more
conceptual
http://eppi.ioe.ac.uk/EPPIWebContent/hp/reports/healthy_eating02/Final_report_web.pdf
Three analytic steps described
1. the coding of text 'line-by-line‘ (data driven codes); 2. the development of 'descriptive themes'; and 3. the generation of 'analytical themes‘ (theory driven
codes).
Synthesis approach
• Findings of each study examined in turn, each sentence or paragraph assigned a descriptive code – “line by line coding” (e.g. children prefer fruit to vegetables) (in NVIVO) 36 initial codes.
• Similarities and differences between codes sought to group them into a hierarchical tree structure.
• New codes were created to capture the meaning of groups of initial codes. 13 descriptive themes.
• A narrative summary of the findings across the studies organized by these 13 descriptive themes was then written.
Policy relevance?
• Reviewers inferred from these themes the factors that help and hinder healthy eating (analytic themes).
Another example of thematic synthesis: Framework synthesis – a priori coding framework
You can design a review specific data extraction template
• Framework synthesis
Other options: You can use a generic data extraction template
Maternal factors that impact on poor child outcomes age 5 years
Source: Using information and intelligence to improve local decision-making for high quality, cost effective services, Child and Maternal Health Observatory
You can extract evidence mapped against a logic model
Key text from1988
Picked up as a method of synthesis in 2002
Definition of synthesis is explicitly interpretative
Activity or the product of activity where some set of parts is combined or integrated into a whole…
(Synthesis) involves some degree of conceptual innovation, or employment of concepts not found in the characterization of the parts as a means of creating the whole
Strike & Posner (1983) quoted in Noblit & Hare (1988)
Translation types I:
• Reciprocal translation - at conceptual level
– “in an iterative fashion, each study is translated into the terms of the others and vice versa”
– “attention to which metaphors, themes, organizers, enable us to fully render the account in a reduced form.”
– Each study inductively coded sequentially
Reciprocal translation
• Similar to constant comparison • Look for overlap, similarities, contradictions• Are some concepts “better”? (scope, utility, explanatory
power). • Reviewer interpretation crucial (third order constructs/
concepts/theory) • Different ways of extracting and juxtaposing concepts
(coding original papers, tabulation, mind maps, colour coding, short text descriptions)
Translation types II:
• Refutational translation– “a specific form of interpretation”– Oppositional/ counter argument findings– Specific search for metaphors, themes, and concepts that
oppose/ refute emerging patterns – extracted and interpreted
Translation types III:
• Line of argument– “What can we say about the whole?” (p. 62)– Development of a new model, theory or understanding through
the synthesis
Stop, think and reflect
• What do you think about the data extraction and synthesis methods presented?
• Which one would you select for your review and why?
• If you have already used a particular method – how did it work?
• Talk to your partner.
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